Hybrid vehicle operations simulator

ABSTRACT

The invention uses an actual mobile vehicle whose operation is to be simulated, combined with computer-based image generation devices, and velocity, acceleration, and/or position measurement tools to improve the simulated operation of the vehicle, including perception of and response to hazards. Using the actual vehicle whose operation is to be simulated improves operator vestibular cues, visual cues, and motion fidelity, thereby producing a safer, less expensive means to produce the simulation.

FIELD OF THE INVENTION

[0001] This invention relates to vehicle simulation, and moreparticularly to methods and apparatus for simulating the human operationof a moving vehicle under selected operating conditions.

BACKGROUND OF THE INVENTION

[0002] Since the advent of computer technology first made them possible,vehicle simulators have been used for a number of purposes, includingresearch, training, and vehicle engineering. Simulators have becomeincreasingly prevalent and useful for reproducing the experience ofoperating aircraft, motor vehicles, trains, spacecraft, and othervehicles. Aviation simulators have become particularly prevalent, withnearly every airline now using simulators for training and research—thefirst time a commercial pilot flies a new aircraft, it is often filledwith passengers. The military services use simulators extensively fortraining personnel in the operation of ships, tanks, aircraft, and othervehicles.

[0003] Despite their varied usage, simulators, especially thoseproviding the operator(s) with motion cues, have primarily remained thetools of large organizations with significant financial resources. Theuse of motor vehicle (i.e., driving) simulators has not yet progressedbeyond manufacturers, suppliers, government agencies (including themilitary), and academic institutions, largely because of their cost.However, driving simulators have a number of valuable safetyapplications. First, they offer research into driver response behavior.Highways are becoming populated by more vehicles, moving at greaterspeeds, with a greater portion of drivers comprised of older adults withreduced sensory and response capabilities. Cellular telephones,navigation systems, and other devices (often developed by third partiesand added to vehicles without suitable integration withmanufacturer-supplied devices) place increased demands on the driver'sattention, and drugs continually arrive on the market that affect driveralertness. These factors mandate a better understanding of driverlimitations, particularly those of older drivers. Researching driverbehavior in emergencies by examination of real accidents has limitedyield, because every accident is unique to some extent, determiningcausation is difficult, and controlled experimental research isinherently not possible for real accidents. Driving simulators couldprovide data on the driver's response to emergency situations withoutexposure to actual risk.

[0004] Second, simulators can provide an improved means for training andevaluating drivers. Most driver training is conducted either inclassrooms or in automobiles in normal traffic, which rarely exposestrainees to unexpected hazards. Devices that would allow trainees toexperience potential collision situations, visibility hazards, or otherunusual driving situations, without actual exposure to risk wouldprovide useful training.

[0005] Third, simulators provide manufacturers and suppliers useful datafrom which to further develop their products. Vehicle manufacturers,suppliers and car/truck fleet owners usually perform developmental testsin actual vehicles, but this is limited to experiences not involvingcollision or other hazards. The use of simulators to perform thesefunctions is costly, particularly for programming and measuring motionand configuring the simulator to represent the appropriate vehicle,limiting the usefulness of these simulators for most researchapplications.

[0006] Simulators are primarily tasked with recreating the sensory cuestheir “real-world experience” counterparts offer. Most state of the artsimulators do a credible job recreating visual and audible stimuli, butonly the most expensive provide credible cues for the vestibular senses(controlled by semicircular canals in the inner ear, which sense rotaryacceleration, and otolith organs, which sense translationalacceleration) and the muscle and joint sensors of motion. Motor vehiclesimulators, in particular, struggle to provide a faithful motionrepresentation without exorbitant cost. Because of the cost of providingsuch functionality, relatively few driving simulators even attempt toprovide motion cues, despite the fact that tests reveal subjects tend toover-steer or experience vertigo because of a mismatch between visualand motion cues. Those that provide motion cues usually do so with anexpensive hydraulic simulator base, but very few motion-base drivingsimulators are in use, and even these lack the ability to accuratelyconvey translational acceleration. Some state of the art simulatorspromise to rectify this problem, but this capability typically entails asignificant cost. Clearly, simulators that represent motion cuesfaithfully are not cost-effective research or training tools for mostapplications.

[0007] The same financial barriers that prevent more widespread use ofdriving simulators have also prevented the development of simulators forthe operation of wheelchairs, skis, snowboards, and many other vehicleswhich move, sometimes at high speeds, when in actual operation. Clearlythe availability of more cost-effective simulators could enable betterresearch, training, and engineering, resulting in safer and moreuser-friendly vehicles, both those indicated above and others, and inbetter, safer operation thereof.

SUMMARY OF THE INVENTION

[0008] The present invention overcomes the cost and motion fidelityissues of other vehicle operation simulators with a novel combination ofexisting devices. In order to generate realistic motion cues, theoperator is carried by and operates an actual vehicle. Vehicle examplesinclude but are not limited to an automobile, motorcycle, aircraft,wheelchair, bicycle, skis, and a ship. According to one aspect of theinvention, the vehicle is operated in a “natural environment” using itsnormal vehicle control, and in accordance with visual and audible cuesprovided by a virtual reality device. The natural environment may be anopen space (e.g., a large field or a parking lot), a track, an unused orseldom used roadway, snow-covered mountain slope, air space, or otherenvironment appropriate for the mobile vehicle being used. The virtualreality device takes advantage of recent advances in computer processingand image generation speeds to create a realistic vehicle operationenvironment, including hazards which are not present in theactual/natural environment. Thus the invention provides realistic motioncues at reasonable cost, thereby creating training, research, andproduct development opportunities not previously possible.

[0009] In its most preferred embodiment, the present invention isoperated in a large, open area free of obstacles and hazards. Since itsintent is to provide a realistic vehicle operation experience, theseareas provide the greatest opportunity to simulate all types ofuninterrupted operation experiences. For example, if the invention wereto simulate the operation of an automobile, it would be difficult tosimulate driving on a highway for any useful period if the inventionwere used in an urban area, or even in a small field. However, forcertain uses, it is envisioned that the invention may be operated oncertain less-trafficked roads or streets.

[0010] The present invention provides both apparatus for a vehicleoperation simulator and a method for simulating vehicle operation. Theapparatus includes a mobile vehicle having vehicle controls, a scenegenerator, and a scene display that receives input from the scenegenerator and presents at least a partial virtual environment view tothe operator of the vehicle. A method for use includes the scenegenerator creating at least one element within an environment view,transmitting an electronic signal comprising the at least one elementwithin the environment view to the scene display, the scene displaypresenting the environment view to the vehicle operator, and, based onresulting operator actuation of vehicle control or vehicle movement,regenerating the environment view to provide continually updated cues tothe operator, including visual and/or audible cues.

[0011] The scene display may present the operator an environment viewconsisting of artificial elements (produced by the scene generator) or acombination of artificial and natural elements. The components of thescene display may, for example, include a head-mounted unit, aprojector, and/or a projection screen which is either partiallytransparent (e.g., half-silvered) or opaque (e.g., a flat screen).Depending on the equipment used, the environment view may consist of aviewable image presented within the head-mounted unit worn by theoperator, an image projected onto flat or curved screens shaped like thewindshield and/or side and rear windows, or images projected onto asemi-transparent screen so as to superimpose artificial elements on theoperator's view of the surrounding natural environment.

[0012] The scene generator transmits an electronic signal to the scenedisplay comprising at least one element within the environment view,which includes the location of natural and artificial images within thedisplay. The scene generator continually regenerates the environmentview for display to the vehicle operator via the scene display. Thescene generator may alter artificial images within the environment viewin response to vehicle movement, operator actuation of vehicle controls,and predetermined artificial image movement. Components of the scenegenerator may include a general-purpose programmed computer, and a meansfor transmitting a signal to the scene display.

[0013] The environment view may be presented to the vehicle operator tosuggest behavior—for example, a velocity—different from the actualbehavior exhibited by the vehicle. In these embodiments, a mechanism maybe employed to allow the vehicle to respond to control actuation asthough the vehicle were behaving as shown in the environment view. Forexample, the environment view might be presented to the operator of anautomobile as though it were traveling at 70 miles per hour, when thevehicle actually is travelling at only 35 miles per hour. This mechanismmight alter the operator's actuation of the steering wheel, for example,to cause a much sharper turn than under normal operation at 35 miles perhour, or at least to provide a simulated view of such a sharper turn.

[0014] The scene generator may take one or more forms of vehicle andoperator movement and/or position data multiple as input. These mayinclude acceleration data from an accelerometer or gyroscopic inertialmeasurement unit, velocity data from a unit which measures eithertranslational or rotational velocity in up to six degrees of freedom, orposition data from a positional measurement unit.

[0015] A mechanism may be used to maintain equivalent light brightnessbetween a natural environment seen outside the vehicle and an imageprojected on such natural environment. For example, embodiments in whichimages are projected on to a semi-transparent screen so as tosuperimpose artificial elements on a natural environment will need tocalibrate the brightness of such images to the brightness of the naturalenvironment in order to present a realistic operating environment. Thismechanism may include a component mounted on the exterior of the vehicleto take light brightness measurements of the natural environment. Thismechanism provides these measurements to the scene generator,continually incorporating any shifting brightness of the environmentinto the generation of artificial images so that they remain realisticunder changing conditions.

[0016] The vehicle may employ secondary vehicle controls to enhanceoperator safety, such that the vehicle responds exclusively to thesecondary controls, or to both controls when the secondary controls areactuated. This secondary vehicle control might be used in instanceswhere only a secondary operator can see the actual movement of thevehicle in relation to the natural environment, and might, in anautomobile for example, include conventional dual controls used indriver training vehicles.

[0017] The vehicle may employ parameter-constraining apparatus that actto restrict the movement of the vehicle or the actuation of vehiclecontrol. In one example, on a wheelchair this apparatus might restrictmovement to prevent it from exceeding certain speeds. In anotherexample, on an airplane this apparatus might restrain control actuationto prevent a roll so sharp it would disorient the operator.

[0018] Further features and advantages of the present invention, as wellas the structure and operation of various embodiments of the presentinvention, are described in detail below with reference to theaccompanying drawings. In these drawings, the same or equivalentreference numerals are used to represent the same element in the variousfigures.

IN THE DRAWINGS

[0019]FIG. 1 is a block diagram of an illustrative embodiment of theinvention.

[0020]FIG. 2 is a view from the operator's perspective of anillustrative embodiment.

[0021]FIG. 3 is a flowchart illustrating operation of the invention.

[0022]FIGS. 4A, 4B, 4C, and 4D are semi-block diagrams illustrating fourdifferent ways in which the invention may be implemented.

DETAILED DESCRIPTION

[0023] Referring to FIG. 1, the vehicle operation simulator for anillustrative embodiment includes a mobile vehicle 100, which may be anyvehicle that moves with at least one degree of freedom, for whichmovement represents an ordinary feature of operation, and which includesat least one component for regulation or control of said movement.Examples include, but are not limited to, an automobile, aircraft, ship,truck, railroad train, motorcycle, wheelchair, bicycle, snowboard,roller skates, and skis. Mobile vehicle 100 may be operated in a naturalenvironment; for example, in an open space appropriate to the mobilevehicle. This open space should be large and preferably free of othervehicles, potential hazards, and pedestrians. However, it is alsocontemplated that the invention be practiced on unused or seldom-usedtracks, streets, air space, snow slopes, roadway, or other environmenton which the particular vehicle 100 might normally be operated.

[0024] A scene generator 130 is provided which generates an electronicsignal and transmits it to scene display 140, which presents anenvironment view 170 to human operator 120. Typically, the scenegenerator includes a programmed general-purpose computer to generateimages and sounds associated with a virtual environment which mayinclude obstacles and hazards, including, but not limited to, othervehicles, animals, people, or fixed objects. These computer-generatedelements typically exhibit behavior and characteristics of theirreal-world counterparts. For example, a computer-generated image of aperson might be animated so as to appear to cross the street in front ofthe mobile vehicle 100. It should be noted that other equipment mightalso provide the functionality of the scene generator 130 including, forexample, an array of projectable photographic or video images.

[0025] In some embodiments, the environment view is completelyartificial. In one example, the environment view may include acomputer-generated artificial background, at least onecomputer-generated artificial element, and have no elements taken fromthe natural environment surrounding the mobile vehicle. In otherembodiments, the environment view may be comprised of a composite ofnatural elements and artificial elements. In one example,computer-generated artificial elements might be superimposed on adisplay screen that also allows the view of a natural environment topass through. In another example, the scene generator would superimposecomputer-generated artificial elements against a backdrop of a colorvideo signal of the actual natural environment, or of a selectivelymodified natural environment. For example, a simulation conducted duringthe day may be modified to simulate night driving. The scene generatormay also receive input on the state of the natural environment from, forexample, vehicle-mounted cameras, and use this input in generating atleast one element within an environment view that is related inpredetermined ways to the actual environment.

[0026] The scene display 140 may take many forms. In some embodiments,the scene display is a head-mounted display that presents theenvironment view in the field of vision of the operator, and allows fora realistic field of vision no matter how the operator's head isoriented or where in his field of vision the operator's eyes arefocused. In other embodiments, the scene display includes an electronicdisplay and/or a projection unit affixed to the vehicle. Either thehead-mounted or fixed display may include a half-silvered mirror,allowing the items projected on to the half-silvered mirror and thenatural environment 180 behind it to comprise the environment view. Inother embodiments, the scene display includes a projection unit and aflat screen, constructing an environment view 170 consisting entirely ofprojected elements. The environment view may consist of images projectedon a single surface or, where appropriate, multiple surfaces. Forexample, the simulation of the operation of a helicopter might requirethe use of multiple display surfaces to present the operator simulatedviews above the airplane and on either side, as well as in front.

[0027] In some embodiments the operator's actuation of vehicle control110 is input to a computerized mathematical model 135, which may run onthe same computer as the scene generator. This mathematical model maythen provide input to scene generator 130, causing the scene generatorto alter the environment view presented on the scene display asappropriate to compensate for vehicle orientation and/or position, andthe operating environment to be simulated.

[0028] Data on vehicle activity may also be provided to the scenegenerator via the measurement unit 150. This unit may measure thevelocity of the vehicle (by measuring, for example, an automobile'swheel rotation and angle), measure its translational or rotationalacceleration (for example, with an accelerometer, inertial accelerationmeasurement unit, or gyroscopic sensors), or measure changes in itsposition (using, for example, a global positioning system device, orlaser triangulation in the operating area). Regardless of themeasurement device used, however, this velocity, acceleration, orposition data will encompass up to six degrees of freedom includingtranslation and rotation. In one example, the measurement unit mightdiscern a ship's velocity by combining measurements of water flow past apredetermined point on the ship's hull with measurements of the rudderangle over time. In another example, the measurement unit might discernan automobile's acceleration or deceleration relative to the groundand/or gyroscopic changes in its heading over time. (The use ofinertial, position, and velocity measurement units will be well-known bythose skilled in the art.) Data from either of these measurement unitsmay supplement or replace input from vehicle control 110 to amathematical model and/or the scene generator. The scene generator maythen alter the environment view as appropriate given the mobilevehicle's movement (i.e., changes in angle or position relative to theearth) using conventional computer graphic transformations of imagegeometry.

[0029] Operator 120 actuates vehicle control 110 to control mobilevehicle 100, triggering cues to the operator's motion sense organs. Someembodiments may employ additional features to ensure the safety of theoperator. For example, air bags and lap belts may be used to secure theoperator in place during operation. Either vehicle control 110, or themotion of mobile vehicle 100, may be constrained byparameter-constraining apparatus 160. The parameter-constrainingapparatus may comprise a computer system designed to assume control ofthe vehicle under certain hazardous conditions, a governor mechanismdesigned to limit vehicle velocity, or a mechanism limiting turn radius,angle of descent and/or other motion parameters. This apparatus mayrestrain motion either totally or in a manner dependent on vehicleoperating conditions. The constraints may limit actuation of vehiclecontrols, but preferably limit the response of the vehicle to thecontrols.

[0030] Depending on the embodiment, scene generator 130 may also takeinput from light brightness measurement unit 190 and video camera 200. Alight brightness measurement unit may provide data enabling the scenegenerator to maintain consistent brightness between the naturalenvironment and any artificial elements that are superimposed.Therefore, this unit may be mounted or otherwise affixed to the vehicleso as to enable measuring the light brightness of the environment viewas seen by the operator, as will be appreciated by those skilled in theart.

[0031] One or more video cameras may provide one or more video signalsdepicting the natural environment, for use when the natural environmentis not otherwise visible to the operator. Therefore the video camera(s)may also be mounted or otherwise positioned on the vehicle's exterior oron the operator's head so as to capture the visible elements of thenatural environment from a perspective collinear with the operator'sfield of vision; methods for appropriate capture of the naturalenvironment using video camera apparatus will also be well-known bythose skilled in the art. While the camera(s) may provide a video imagedirectly to scene display 140, it is preferable that camera output beprovided, as shown, to scene generator 130, where it may be used toreproduce either the actual—or a modified version of—the naturalenvironment.

[0032]FIG. 2 depicts the interior of mobile vehicle 100 which, for theillustrative embodiment, is automobile 200 with controls 210 including asteering wheel, an accelerator, a brake, and other suitable controlssuch as a gear shift, clutch, de-fogger, etc. (controls not shown).Scene generator 130 may be a programmed general-purpose computer storedwithin automobile 200. A half-silvered mirror 220, integrated with orseparate from the vehicle's windshield, or attached to the head-mounteddisplay, receives either projected images from a projector (not shown)situated within automobile 200 (in the case of a screen display), or asignal from the scene generator (in the case of the head-mounteddisplay). Either the image projector or the head-mounted unit, combinedwith the half-silvered mirror 220, form scene display 140. Obstacles 240are placed in the environment view such that it appears superimposed onthe natural environment also viewable through the half-silvered mirror220.

[0033] Some embodiments may also include a secondary vehicle control 230to promote the safe operation of the automobile. A secondary vehicleoperator, who monitors the operator's actions and corrects or overridesvehicle control actuation that would result in danger or injury,operates secondary vehicle control 230. The secondary operator mayexperience the same environment view as the operator, may experienceonly the natural environment, may experience both environments (forexample, on a split screen view), or may experience some other viewappropriate to maximize safe operation of the vehicle.

[0034]FIG. 3 is a flow diagram of a method for simulating vehicleoperation utilizing the apparatus of FIG. 1. In step 310 an environmentview is created, which may consist of artificial elements designed towholly comprise the environment view, or artificial elements intended tobe superimposed on natural elements to comprise the environment view.The scene generator transmits these elements to the scene display. Instep 320, the scene display presents the environment view to theoperator. In some embodiments, if scene display is accomplished viaprojection on a viewing surface, the viewing surface may encompass thefield of vision regardless of the operator's head movement—i.e., theviewing surface will allow the operator to see a projected image in allrelevant directions for the particular vehicle.

[0035] In step 330, the operator actuates vehicle control in accordancewith the environment view. The actuation of vehicle control will includeat least one operator act—for example, applying rotational force to asteering wheel, controlling force on an accelerator, applying force to abrake pedal, applying force on one edge of a snowboard, and/or applyingforce on the control stick of an airplane.

[0036] As shown in step 340, the vehicle responds to actuation of thevehicle control. In some instances, parameter-restraining apparatus maybe employed to restrict vehicle movement, to enhance operator safety orfor other reasons. This apparatus may act to restrain control actuationby, for example, preventing the operator from applying more than apredetermined downward force on the accelerator, or from applying morethan a predetermined rotational force on the steering wheel. Thisapparatus may alternatively (or in addition) restrict vehicle movementresulting from operation of the control by, for example, preventing thevehicle from exceeding a predetermined speed or executing an overlysharp turn. The scene generator may react to the controls as operated,or to the constrained control operation or vehicle movement.

[0037] The actuation of vehicle control in step 330 and/or vehiclemovement in step 340 will provide input to the regeneration of theenvironment view in step 310. If the environment view responds tocontrol actuation, sensors on one or more vehicle controls may provideinput to a mathematical model of vehicle activity, which in turnprovides input to the scene generator. If the environment view respondsto vehicle movement, a measurement unit mounted on the vehicle mayprovide input to the scene generator. In either case, the scenegenerator processes this input to update at least some elements withinthe environment view, and the scene display presents the environmentview to the operator. The frequency of this update will vary based onthe processing power of the computer within the scene generator, but maytake place thousands of times per second.

[0038] In some embodiments, the scene generator may create elements ofan environment view that do not coincide with the actual behavior of thevehicle. In these embodiments, a mechanism may supplement, detract from,or otherwise alter the force applied by the operator to actuate vehiclecontrol and/or the vehicle response to such actuation, in order tosimulate vehicle control actuation under the conditions presented in theenvironment view. For example, if the environment view is presented tosimulate an automobile moving at 70 miles per hour, but the vehicle isactually moving at 35 miles per hour, a mechanism may translate arotational force the operator applies to the steering wheel to a muchsharper actual turn of the front axle, consistent with a velocity of 70miles per hour. Also, for example, if the environment view is presentedto simulate an automobile traveling in the snow, a mechanism maytranslate the downward force applied to the brake pedal to a much weakerforce, or otherwise alter the force, actually applied to the brake padsto simulate deceleration in slippery conditions. Those skilled in theart will be able to offer several methods through which this may beaccomplished. Regardless of the method employed, data on the operator'sactuation of vehicle control will be fed to the scene generator forcontinual regeneration of the environment view.

[0039] FIGS. 4A-4D depict alternative components suitable for use inimplementing the apparatus depicted in FIG. 1. Components within FIGS.4A-4D are numbered according to the corresponding component from FIG. 1and given alphabetic suffixes corresponding to the specific figure. Insome instances, particular components shown in FIG. 1 comprise more thanone component shown in FIGS. 4A-4D; in these instances identifiers areassigned in FIGS. 4A-4D so as to indicate a numeric association betweenthe components For example, scene display 140 in FIG. 1 equates to scenedisplay half-silvered mirror 143B and scene display projector 145B inFIG. 4B.

[0040] Referring to FIG. 4A, operator 120A wears head-mounted scenedisplay 140A. This head-mounted display receives a signal from scenegenerator 130A. Depending on the vehicle whose operation is to besimulated, the display may consist of, for example, a roughly planarsurface and three-dimensional elements therein (for simulation ofautomobile operation, for instance), or a relatively unobstructed viewof the open space before the vehicle (for an airplane, for instance).The head-mounted display and scene generator are capable of presentingthe vehicle operator with an environment view commensurate with headmovement toward the left, right, up, or down, and commensurate withvehicle movement, since the operator remains in a relatively fixedposition within the vehicle. At any one time, however, it presents theoperator with an environment view comprised of the operator's field ofvision given his/her head orientation. Thus, the operator's environmentview varies as a function of both vehicle movement or position, and ofhead movement or position.

[0041] The inertial measurement unit (IMU) 150A ascertains accelerationof both the vehicle and the operator's head, and provides this input toscene generator 130A so as to regenerate the environment view forrendering on the head-mounted scene display. The scene generatormaintains a realistic simulation of the operator's field of vision byaccepting data on head and vehicle acceleration from the IMU,regenerating the environment view based on this data, and transmittingit to the head-mounted scene display 140A. Those skilled in the art willbe able to offer several alternatives for how the transmission ofvelocity data from the IMU to the scene generator might be accomplished.Those skilled in the art will also be able to offer suitable powersources for the scene generator, IMU, head display, and video camera,such that the risk of equipment failure and resulting operator dangerdue to power outage is minimized.

[0042] Depending on the vehicle used, and other factors, the scenegenerator may be secured within the vehicle, or may be a portable unitthat can be worn or otherwise held by the operator while the mobilevehicle is in motion.

[0043]FIG. 4B depicts another illustrative embodiment of the invention,wherein operator 120B observes the environment view throughhalf-silvered mirror 143B, which is sufficiently transparent to allowthe operator to view the natural environment 180B through it, andsufficiently opaque to allow the operator to view artificial imagesprojected by scene display projector 145B. The scene generator 130Btransmits a signal consisting of artificial elements to be displayed andtheir location in the environment view, among other data, to the scenedisplay projector, and the scene display projector projects the image onhalf-silvered mirror 143B. Thus the composite image/environment view170B viewed by an operator is a combination of natural elements from thescene ahead and superimposed artificial elements projected by the scenedisplay projector.

[0044] Although the half-silvered mirror is depicted in FIG. 4B as aflat, windshield-like screen, other embodiments might employ acylindrical half-silvered mirror mounted to the vehicle structure, acylindrical half-silvered mirror mounted to the operator's head, orother variations.

[0045] The measurement unit 150B provides input on the vehicle'svelocity to the scene generator so that artificial elements within theenvironment view can be updated appropriately for presentation by thescene display projector. The scene generator accepts this input on thevehicle's position to continually regenerate the environment view.

[0046] A light brightness equivalence mechanism 190B measures theintensity of light outside the vehicle and provides this input to thescene generator. The scene generator then adjusts the brightness ofimages to be superimposed by scene display projector 145B, so thatcomposite image 170B constitutes a realistic rendering of an operatingenvironment. This aspect of the invention may be especially importantfor vehicle operation during periods of low sunlight, during periods ofespecially bright daylight, or in instances of high glare.

[0047] The scene generator, the scene display projector, the measurementunit and the light brightness equivalence mechanism may be stored withinor mounted upon the vehicle.

[0048]FIG. 4C depicts another embodiment of the invention, which is thesame as FIG. 4A except that the scene generator 130C receives input fromvideo camera 200C, which is mounted on the operator's head so as to becollinear with the operator's view. This video signal may depict thenatural environment, or it may be altered before presentation to theoperator in a predetermined fashion. In an illustrative embodiment,scene generator 130C alters the signal sent by video camera 200C toinsert artificial elements and their location into the environment view,and in some cases also makes selected variations in the naturalenvironment. Thus, operation of the vehicle at night might be simulatedduring daylight hours. This altered signal is then input to head-mountedscene display 140C. A scene generator may be mounted on or within thevehicle, or may be a portable unit that can be worn or otherwise held bythe operator while the vehicle is in motion.

[0049] The inertial measurement unit 150C affixed to the head-mounteddisplay provides input on the acceleration of the vehicle and/or theoperator's head. When the head-mounted display is used, additionalmeasurement of head orientation or position, and/or of operator positionwithin the vehicle, may be provided by means of an electromagneticsensor and/or mechanical linkage sensor with a potentiometer (not shown)affixed to the vehicle. This may prove useful for simulating theoperation of a vehicle which may requires the operator to move aboutwithin the vehicle's interior (e.g., a ship or railroad car). The scenegenerator will combine data provided by the sensor(s) and othermeasurements of the vehicle's and operator's position to provide anaccurate environment view to the operator.

[0050]FIG. 4D depicts another embodiment of the invention, which islargely the same as FIG. 4B except that video camera 200D provides inputto scene generator 130D in the form of a video image collinear with theoperator's view, and operator 120D views an image projected on flatscreen 140D. A measurement unit 150D transmits input on vehicleposition, provided by means which may include a global positioningsystem (GPS) unit, laser triangulation within the operating area, orother position measurement techniques, to the scene generator. In apreferred embodiment, the scene generator manipulates the signal sent bythe video camera, which may depict the natural environment, to insertartificial elements and their location. This altered signal is then fedto scene display projector 140D, which projects environment view 170D onto the flat screen.

[0051] While in the discussion above, head and vehicle movement andposition have been measured to control the scene generator, in someapplications other movements may be monitored, as appropriate, toprovide a realistic simulation of vehicle operation. Thus, while theinvention has been particularly shown and described with reference tospecific embodiments, and variations thereon have been indicated, itshould be understood by those skilled in the art that various additionalchanges in form and detail may be made therein without departing fromthe spirit and scope of the invention as defined by the followingclaims.

What is claimed is:
 1. A vehicle operation simulator comprising: amobile vehicle operable in a natural environment having at least onevehicle control; a scene generator; a scene display in communicationwith said scene generator and viewable by a vehicle operator, anenvironment view being presented on said scene display which is createdat least in part by said scene generator; and wherein said mobilevehicle carries the operator and is controlled by the operator inaccordance with said environment view, said mobile vehicle responding toactuation of said at least one vehicle control and said environment viewresponding to at least one of operation of said at least one vehiclecontrol, operator movement, and vehicle movement.
 2. The vehicleoperation simulator of claim 1 including at least one of an inertialacceleration measurement unit, a gyroscopic measurement unit, and apendulum, responding to motion of said mobile vehicle in up to sixdegrees of freedom to provide input to said scene generator.
 3. Thevehicle operation simulator of claim 1 including at least one of aninertial acceleration measurement unit, a gyroscopic measurement unit,and a pendulum, responding to motion of said operator's head in up tosix degrees of freedom to provide input to said scene generator.
 4. Thevehicle operation simulator of claim 1 including a measurement unitresponding to a velocity of said mobile vehicle in up to six degrees offreedom to provide input to said scene generator.
 5. The vehicleoperation simulator of claim 1 including at least one of a globalpositioning system unit and a laser triangulation unit, responding tochanges in position of said mobile vehicle in up to six degrees offreedom to provide input to said scene generator.
 6. The vehicleoperation simulator of claim 5 including at least one of anelectromagnetic arm, a mechanical arm with potentiometer, and magneticsensors, responding to changes in position of said operator's head inrelation to said mobile vehicle in up to six degrees of freedom toprovide input to said scene generator.
 7. The vehicle operationsimulator of claim 1 including a computer-based mathematical model ofactivity of said vehicle, responding to at least one of said vehiclecontrol and movement of said vehicle, to provide data on at least one ofposition of said vehicle in up to six degrees of freedom as input tosaid scene generator.
 8. The vehicle operation simulator of claim 1wherein said environment view is wholly comprised of elements from saidscene generator.
 9. The vehicle operation simulator of claim 8 whereinsaid scene display is affixed to at least one of said mobile vehicle anda head-mounted display worn by the vehicle operator.
 10. The vehicleoperation simulator of claim 1 wherein said environment view is acomposite of at least one element from said scene generator, and atleast one element from the natural environment.
 11. The vehicleoperation simulator of claim 10 wherein said at least one element fromthe natural environment is captured with a video camera and input tosaid scene generator.
 12. The vehicle operation simulator of claim 10wherein said at least one element from the natural environment isvisible to said operator through a partially transparent viewing screen.13. The vehicle operation simulator of claim 12 wherein the viewingscreen is affixed to at least one of the mobile vehicle and ahead-mounted display worn by the vehicle operator.
 14. The vehicleoperation simulator of claim 10 wherein said scene generator includes amechanism maintaining equivalent light brightness between at least oneelement from said scene display and the natural environment.
 15. Thevehicle operation simulator of claim 1 wherein the at least one elementpresented in said environment view differ in a controlled fashion fromthe actual behavior of said mobile vehicle.
 16. The vehicle operationsimulator of claim 15 wherein the vehicle responds to operator actuationof vehicle control in accordance with movement represented in saidenvironment view rather than the movement of said vehicle.
 17. Thevehicle operation simulator of claim 1 including one or more sensorsresponding to movement of said operator within said mobile vehicle toprovide input to said scene generator and said scene display.
 18. Thevehicle operation simulator of claim 1 including secondary vehiclecontrol for said mobile vehicle, said secondary vehicle control to beactuated by a second operator.
 19. The vehicle operation simulator ofclaim 18 wherein said mobile vehicle responds exclusively to saidsecondary vehicle control when said secondary vehicle control isactuated.
 20. The vehicle operation simulator of claim 18 wherein saidmobile vehicle selectively responds to both said secondary vehiclecontrol and said vehicle control when said secondary vehicle control isactuated.
 21. The vehicle operation simulator of claim 1 includingparameter-constraining apparatus limiting at least one of the movementof said mobile vehicle and the actuation of said vehicle control. 22.The vehicle operation simulator of claim 1 wherein said scene displayincludes at least one of a mirror, a flat opaque viewing screen, acurved opaque viewing screen, and electronic display, and a partiallytransparent half-silvered mirror.
 23. A method for simulated operationof a vehicle in a natural environment including the steps: (a)generating an environment view; (b) presenting the environment view toan operator carried by a mobile vehicle, said mobile vehicle operatingin a natural environment; (c) the operator actuating controls for saidmobile vehicle, movement of said mobile vehicle responding to saidactuation; and (d) altering said environment view in response to atleast one of vehicle movement, operator actuation of controls, operatorhead movement, and operator movement within said vehicle.
 24. The methodof claim 23 wherein the elements presented in said environment viewdiffer in a controlled fashion from those commensurate with the actualbehavior of said mobile vehicle.
 25. The method of claim 23 wherein saidenvironment view comprises at least one element rendered by said scenegenerator and at least one element from the natural environment.
 26. Themethod of claim 25 wherein step (a) includes maintaining equivalentlight brightness between at least one element from said scene displayand the natural environment.
 27. The method of claim 23 wherein saidenvironment view is wholly comprised of elements from said scenegenerator.
 28. The method of claim 23 wherein said vehicle has secondaryvehicle control, and including the step of said secondary vehiclecontrol being actuated by a second operator under selected conditions.29. The method of claim 28 wherein said mobile vehicle respondsexclusively to said secondary vehicle control when said secondaryvehicle control is actuated.
 30. The method of claim 28 wherein saidmobile vehicle selectively responds to both said secondary vehiclecontrol and said vehicle control when said secondary vehicle control isactuated.
 31. The method of claim 23 wherein said environment view ispresented on at least one of a scene display affixed to said mobilevehicle and a head-mounted display worn by the vehicle operator.
 32. Themethod of claim 23 wherein step (c) includes limiting at least one ofthe movement of said mobile vehicle and actuation of said vehiclecontrol.